The Original, often-copied, genuine B-316 Series directional control valve. The Versa B316 Series is a complete line of compact, rugged Three-Way (3/2), side-ported valves, constructed of 316 stainless steel (conforms to NACE standard MR-01-75). They are designed for use particularly in corrosive environments and to control a variety of aggressive media as well as air. O ring packed poppets provide bubbletight sealing throughout the operating pressure range and when used to operate small volume appliances this feature conserves valuable instrument air.